I'm sure you all have heard that there is now a free ASP.NET charting control that is an add-on to ASP.NET 3.5. If you haven't or need one of the bits, check out ScottGu's blog. I recently started using the component and it's really nice. While working with it, I ran into an issue formatting Date values in the tooltips, so I figured I would share my findings.
In order to format the tooltips, I needed to use one of the supported keywords in order to get the proper value (#VALX). I used an example from the samples as a guide when formatting my tooltip. The chart from the samples shows a chart like the one in the picture off to the left with the tooltip and multiple formatting. Based on the samples, I had the following code in my ASPX. More...